全文获取类型
收费全文 | 389篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
化学 | 191篇 |
晶体学 | 3篇 |
力学 | 13篇 |
数学 | 128篇 |
物理学 | 56篇 |
出版年
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 16篇 |
2006年 | 12篇 |
2005年 | 13篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 7篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1984年 | 14篇 |
1983年 | 7篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1966年 | 5篇 |
1965年 | 3篇 |
1963年 | 5篇 |
1956年 | 3篇 |
1955年 | 3篇 |
1942年 | 8篇 |
1941年 | 5篇 |
1940年 | 4篇 |
1939年 | 2篇 |
排序方式: 共有391条查询结果,搜索用时 31 毫秒
101.
An approximation formula to one in M/M/1 queueing theory for hours in a queue is examined. Then it is extended to models M/D/1 and M/E k /1 whereby wasted time or queue length is found to lie between two extremes. An empirical approximation to traffic intensity called utilization rate is used. 相似文献
102.
P. S. N. Murty K. V. Subbaiah P. V. Subba Rao 《Reaction Kinetics and Catalysis Letters》1979,11(1):79-83
The reaction is first order in potassium peroxydisulfate and zero order in Indigo Carmine. Hydrogen ions have no effect on the rate in the acidity range of 0.0–0.2 M. Allyl acetate inhibits the reaction. A radical chain mechanism is proposed.
. 0 0,2 M . . .相似文献
103.
Several mixed ligand complexes of nickel(II) and cobalt(II) acetylacetonates with N-substituted thioureas such as ortho, meta
and para chlorophenyl, parabromophenyl and orthotolyl thioureas and N,N′-substituted thioureas such as N-benzoyl N′-ethyl
thiourea, N-benzoyl N′-phenyl thiourea, N-benzoyl N′-o-chlorophenyl thiourea, N-benzoyl N′-o-tolyl thiourea, N-benzoyl N′-o-methoxyphenyl thiourea, N-benzoyl N′-cyclohexyl thiourea, N-benzoyl N′-2,5 dimethoxyphenyl thiourea, N-benzoyl N′-2,5 diethoxyphenyl
thiourea, N-benzoyl N′-β-hydroxyethyl thiourea, N-benzoyl N′-furfuryl thiourea, N-benzoyl N′-orthohydroxyphenyl thiourea and
N-phenyl N′-orthomethoxyphenyl thiourea, have been synthesized and characterized on the basis of elemental analysis, conductivity,
molecular weight determination and magnetic moments. The nature of the bonding and the structure of the complexes have been
proposed from the infrared and electronic spectral studies. 相似文献
104.
Murty A.R.C. Bulusu Peter Waldstätten Gerhard Schulz Maximilian Grassberger 《Tetrahedron letters》2004,45(12):2523-2526
Irradiation of ascomycin 1a and its derivatives in MeOH, EtOH and propanol resulted in alkoxylation of the pipecolic acid moiety in the ε-position with concomitant reduction in the tricarbonyl region leading to 6-alkoxy-9-hydroxy derivatives in high stereoselectivities and good yields. The products, after reoxidation of the C(9)-OH, afforded the 6-alkoxy analogues of the parent compounds. Elimination of MeOH from the photoproducts, followed by oxidation gave the corresponding 5,6-dehydro amino acid analogues. Similarly, starting from the proline analogue 7 modifications in the pyrrolidine moiety could be achieved. 相似文献
105.
Krishna BS Mahadevaiah N Murty DS Prakash BS 《Journal of colloid and interface science》2004,271(2):270-276
Removal of lead ( Pb2+ ) ions from aqueous solution by adsorption onto surfactant-immobilized interlayer species bonded to montmorillonite clay (SIIS-clay) was investigated. Surfactant-immobilized interlayer chromate bound to clay (SIICr-clay) was prepared by treatment of montmorillonite clay with hexadecyltrimethylammonium (HDTMA) bromide followed by chromate adsorption at the intergallery framework of the clay. Experiments were carried out as a function of solution pH, solute concentration, and temperature (5-45 degrees C). The Dubinin-Kaganer-Radushkevich (DKR) model was adopted to describe the single-solute adsorption isotherms. Adsorption energy for lead ions on SIICr-clay computed from the DKR equation shows that a precipitation mechanism was operative. The thermodynamic parameters ( Delta G 0, Delta H 0, and Delta S 0) for lead ion adsorption on SIICr-clay were also determined from the temperature dependence. The kinetics of metal ion adsorption was examined and the first-order rate constant was finally evaluated. Adsorbed lead ions could be recovered completely on leaching with the disodium salt of ethylenediamine tetraacetic acid (EDTA) solution and the adsorbent was found to readsorb lead ions repeatedly after leaching. Thus, surfactant-modified smectite clays offer an effective method for designing a recyclable adsorbent for lead ions. 相似文献
106.
A. Ruff A. Krynicki R. C. Parker A. Inst F. J. Siddle N. N. Murty H. K. Sen H. Weinberger H. Gardner E. W. Plowman K. Würth G. Schröder C. E. Foss J. A. V. Fairbrother R. G. W. Croney E. A. Becker L. I. Belenki I. I. Ssokolow M. Je. Kasanskaja N. Bunzelman A. Iljina W. Schwedowa G. Agibalowa M. Déribéré F. Vlès E. Vellinger J. Kasarnowsky K. Allison J. McGray und A. Nicollet 《Fresenius' Journal of Analytical Chemistry》1941,121(7-8):274-281
Ohne Zusammenfassung 相似文献
107.
108.
109.
110.